“Lighter pigmentary traits, such as lighter hair, lighter skin, and severe skin reaction following sun exposure, have been tied to higher risk for skin cancers,” explains Eunyoung Cho, ScD. “However, research on the relationship between eye color and risk for skin cancer has been inconsistent, and few studies look at eye color and risks for basal cell carcinoma (BCC) and squamous cell carcinoma (SCC).”
For a paper published in Cancer Causes & Control, Dr. Cho; Yueyao Li, PhD, MD, MSPH; and colleagues sought to fill the knowledge gap about the association of eye color and the risk for skin cancers. They conducted a prospective analysis using the Health Professionals Follow-up Study (HPFS), consisting of 35,662 male health professionals. Cox proportional hazard models were used to estimate relative risks (RRs) and associated 95% CIs. Effect modifications related to hair color and skin reaction to sun were also analyzed. Over a median follow-up of 19 years (1988–2012), 445 melanomas, 1,123 SCC, and 7,198 BCC cases were identified.
No Significant Link Between Eye Color and Melanoma
“We found that, compared with those whose eye colors were dark or brown, participants with hazel/green/medium and blue/light colors had a 24% (RR=1.24; 95% CI, 1.06–1.45) and a 19% (RR=1.19; 95% CI, 1.01–1.41) greater risk for SCC, respectively,” Dr. Li says. “Likewise, an increased risk for BCC was seen in participants with hazel/green/medium eye colors (RR=1.16; 95% CI, 1.09–1.23) and blue/light eye colors (RR=1.17; 95% CI, 1.10–1.25). We did not identify significant associations between eye color and risk for melanoma. Lighter eye color was also associated with higher risks for SCC and BCC in those with dark hair colors.”
In addition to eye pigmentation, the researchers found that worse skin reaction to sun is a risk factor for skin cancer. “Lighter eye colors in combination with worse skin reaction to sun were regularly tied to increased risks for skin cancer,” says Dr. Cho. “Compared with those with brown/dark eyes whose skin tans after sun exposure, the risks for all three skin cancers were generally higher in other eye color and skin reaction combinations. Participants with blue/light eye color whose skin peels after sun exposure had the highest risk for melanoma, SCC, and BCC. Lighter eye colors were linked to an increased risk for skin cancer, regardless of skin reaction to sun. However, the interaction between eye color and skin reaction to sun was statistically significant only for the risk for BCC, not for SCC or melanoma (Table).”
General Population Research Needed
The results indicate that eye color may serve as an additional indicator for increased skin cancer risk, especially for people with naturally light hair colors and those with a worse skin reaction to the sun, Dr. Cho concludes. “We hope this information will assist dermatologists in identifying individuals with high risk for skin cancer,” she says.
The study team points out that the study has some limitations. “Self-reported data such as eye color and skin reactions to the sun during childhood may be incorrectly categorized,” Dr. Li notes. “Second, the diagnosis of BCC was based on self-report only and may also be subject to misclassification. However, if such misclassifications are present, it should be non-differential, which would have diminished the true associations, and drove our results towards the null. Furthermore, the validity of self-reported BCC was high in the HPFS, as it consists of a medically knowledgeable population.”
Finally, our data was obtained from male health professionals with high health awareness and therefore may not represent the general population. The biological association between eye color and skin cancer may not differ based on health awareness, however. We do agree that further studies are needed to confirm our findings in other populations, including females.”